This invention relates to an assembly for mounting a take-off branch or conduit to a primary pipe, for example a sewage disposal pipe.
Some known assemblies of this type comprise a connection member having a sole plate at its base, with an orifice in the sole plate being disposed opposite an aperture in the wall of the primary pipe. A gasket surrounds the base of the connection member to provide a seal between such member and the outer surface of the pipe, and fastening means are provided to anchor the connection member to the pipe.
With the gasket disposed on the outer surface of the pipe sealing defects attributable to the gasket extending within the interior of the pipe are avoided. In fact, sewage disposal pipes are typically made of centrifuged iron and are covered on the inside with a concrete grout or a centrifuged mortar to prevent the corrosion of the iron. When a branch aperture is cut out from such a pipe, the inner covering can easily crack and typically leaves a jagged edge, and an interiorly disposed gasket is thus not capable of providing a tight seal.
While an exteriorly disposed gasket is therefore advantageous in mounting take-off branches to pipes of this type, sealing problems are still encountered, especially above internal pressures of 1.2 to 1.3 bars, and the structure for rigidly fastening the connection member to the pipe is typically complicated and costly, and is relatively difficult and tedious to install. Moreover, these conventional mounting assemblies do not enable periodic retightening to compensate for production tolerances arising from the dimensions of the aperture in the primary pipe. Such tolerances cause considerable variation in the compression of the gasket, which adversely affects its sealing performance.